1. **Determine if each number is rational or irrational:**
a) $\sqrt{\frac{49}{16}}$
- Step 1: Simplify the square root of a fraction using $\sqrt{\frac{a}{b}} = \frac{\sqrt{a}}{\sqrt{b}}$.
$$\sqrt{\frac{49}{16}} = \frac{\sqrt{49}}{\sqrt{16}}$$
- Step 2: Calculate the square roots.
$$\frac{7}{4}$$
- Step 3: Since $\frac{7}{4}$ is a ratio of two integers, it is a rational number.
b) $\sqrt[3]{-30}$
- Step 1: Cube roots of negative numbers are defined and equal to the negative of the cube root of the positive number.
$$\sqrt[3]{-30} = -\sqrt[3]{30}$$
- Step 2: Since 30 is not a perfect cube, $\sqrt[3]{30}$ is irrational.
- Step 3: Therefore, $\sqrt[3]{-30}$ is irrational.
c) $1.21$
- Step 1: $1.21$ is a terminating decimal.
- Step 2: All terminating decimals are rational numbers because they can be expressed as fractions.
- Step 3: $1.21 = \frac{121}{100}$, so it is rational.
2. **Order the numbers from least to greatest:** $\sqrt{2}$, $\sqrt[3]{-2}$, $\sqrt{6}$, $\sqrt{11}$, $\sqrt{30}$
- Step 1: Approximate each value.
$$\sqrt{2} \approx 1.414$$
$$\sqrt[3]{-2} \approx -1.26$$
$$\sqrt{6} \approx 2.449$$
$$\sqrt{11} \approx 3.317$$
$$\sqrt{30} \approx 5.477$$
- Step 2: Order from least to greatest:
$$\sqrt[3]{-2} < \sqrt{2} < \sqrt{6} < \sqrt{11} < \sqrt{30}$$
3. **Simplify each radical:**
a) $\sqrt{63}$
- Step 1: Factor 63 into $9 \times 7$.
- Step 2: Use $\sqrt{ab} = \sqrt{a} \times \sqrt{b}$.
$$\sqrt{63} = \sqrt{9 \times 7} = \sqrt{9} \times \sqrt{7} = 3\sqrt{7}$$
b) $\sqrt[3]{108}$
- Step 1: Factor 108 into $27 \times 4$.
- Step 2: Use $\sqrt[3]{ab} = \sqrt[3]{a} \times \sqrt[3]{b}$.
$$\sqrt[3]{108} = \sqrt[3]{27 \times 4} = \sqrt[3]{27} \times \sqrt[3]{4} = 3\sqrt[3]{4}$$
c) $\sqrt[4]{128}$
- Step 1: Factor 128 into $16 \times 8$.
- Step 2: Use $\sqrt[4]{ab} = \sqrt[4]{a} \times \sqrt[4]{b}$.
$$\sqrt[4]{128} = \sqrt[4]{16 \times 8} = \sqrt[4]{16} \times \sqrt[4]{8} = 2\sqrt[4]{8}$$
4. **Write each radical in simplest form if possible:**
a) $\sqrt{30}$
- Step 1: 30 factors into $2 \times 3 \times 5$, no perfect square factors.
- Step 2: So, $\sqrt{30}$ is already in simplest form.
b) $\sqrt[3]{32}$
- Step 1: 32 is $2^5$.
- Step 2: $\sqrt[3]{32} = \sqrt[3]{2^5} = 2^{5/3} = 2^{1 + 2/3} = 2 \times 2^{2/3} = 2\sqrt[3]{4}$
c) $\sqrt[4]{48}$
- Step 1: 48 factors into $16 \times 3$.
- Step 2: $\sqrt[4]{48} = \sqrt[4]{16 \times 3} = \sqrt[4]{16} \times \sqrt[4]{3} = 2 \sqrt[4]{3}$
5. **Write each mixed radical as an entire radical:**
a) $7\sqrt{3}$
- Step 1: Write 7 as $\sqrt{49}$.
- Step 2: $7\sqrt{3} = \sqrt{49} \times \sqrt{3} = \sqrt{49 \times 3} = \sqrt{147}$
b) $2\sqrt[3]{4}$
- Step 1: Write 2 as $\sqrt[3]{8}$.
- Step 2: $2\sqrt[3]{4} = \sqrt[3]{8} \times \sqrt[3]{4} = \sqrt[3]{8 \times 4} = \sqrt[3]{32}$
c) $2^{5}\sqrt[5]{3}$
- Step 1: Write $2^{5}$ as $\sqrt[5]{2^{25}}$ because $\sqrt[5]{2^{25}} = 2^{25/5} = 2^{5}$.
- Step 2: Multiply inside the radical:
$$2^{5}\sqrt[5]{3} = \sqrt[5]{2^{25}} \times \sqrt[5]{3} = \sqrt[5]{2^{25} \times 3} = \sqrt[5]{3 \times 2^{25}}$$
6. **Simplify and evaluate without a calculator:**
a) $1000^{1/3}$
- Step 1: $1000 = 10^3$
- Step 2: $1000^{1/3} = (10^3)^{1/3} = 10^{3 \times \frac{1}{3}} = 10^1 = 10$
b) $0.25^{1/2}$
- Step 1: $0.25 = \frac{1}{4} = (\frac{1}{2})^2$
- Step 2: $0.25^{1/2} = \left((\frac{1}{2})^2\right)^{1/2} = (\frac{1}{2})^{2 \times \frac{1}{2}} = \frac{1}{2}$
c) $(-8)^{1/3}$
- Step 1: Cube root of -8 is -2 because $(-2)^3 = -8$
- Step 2: $(-8)^{1/3} = -2$
d) $\left(\frac{16}{81}\right)^{1/4}$
- Step 1: $16 = 2^4$, $81 = 3^4$
- Step 2: $\left(\frac{16}{81}\right)^{1/4} = \frac{16^{1/4}}{81^{1/4}} = \frac{2}{3}$
7. **Write $26^{5/2}$ in radical form in 2 ways:**
- Way 1: $26^{5/2} = \left(26^{1/2}\right)^5 = \left(\sqrt{26}\right)^5$
- Way 2: $26^{5/2} = \sqrt{26^5}$
8. **Write $\sqrt{6}$ and $\left(\sqrt[4]{19}\right)^3$ in exponent form:**
- $\sqrt{6} = 6^{1/2}$
- $\left(\sqrt[4]{19}\right)^3 = \left(19^{1/4}\right)^3 = 19^{3/4}$
9. **Evaluate:**
a) $0.01^{3/2}$
- Step 1: $0.01 = 10^{-2}$
- Step 2: $0.01^{3/2} = (10^{-2})^{3/2} = 10^{-3} = 0.001$
b) $(-27)^{4/3}$
- Step 1: $(-27)^{4/3} = \left((-27)^{1/3}\right)^4$
- Step 2: Cube root of -27 is -3
- Step 3: $(-3)^4 = 81$
c) $81^{3/4}$
- Step 1: $81 = 3^4$
- Step 2: $81^{3/4} = (3^4)^{3/4} = 3^{4 \times \frac{3}{4}} = 3^3 = 27$
d) $0.75^{1.2}$
- Step 1: Approximate $0.75^{1.2}$ using logarithms or calculator (approximate value)
- Step 2: $0.75^{1.2} \approx 0.68$
10. **Use formula $b = 0.01 m^{2/3}$ to estimate brain mass:**
a) Moose with $m=512$ kg
- Step 1: Calculate $512^{2/3}$
- Step 2: $512 = 8^3$, so $512^{1/3} = 8$
- Step 3: $512^{2/3} = (512^{1/3})^2 = 8^2 = 64$
- Step 4: $b = 0.01 \times 64 = 0.64$
b) Cat with $m=5$ kg
- Step 1: Calculate $5^{2/3}$
- Step 2: $5^{1/3} \approx 1.71$
- Step 3: $5^{2/3} = (5^{1/3})^2 \approx 1.71^2 = 2.92$
- Step 4: $b = 0.01 \times 2.92 = 0.0292$
Final answers summarized:
- 1a) Rational
- 1b) Irrational
- 1c) Rational
- 2) $\sqrt[3]{-2} < \sqrt{2} < \sqrt{6} < \sqrt{11} < \sqrt{30}$
- 3a) $3\sqrt{7}$
- 3b) $3\sqrt[3]{4}$
- 3c) $2\sqrt[4]{8}$
- 4a) $\sqrt{30}$ (simplest)
- 4b) $2\sqrt[3]{4}$
- 4c) $2\sqrt[4]{3}$
- 5a) $\sqrt{147}$
- 5b) $\sqrt[3]{32}$
- 5c) $\sqrt[5]{3 \times 2^{25}}$
- 6a) 10
- 6b) $\frac{1}{2}$
- 6c) -2
- 6d) $\frac{2}{3}$
- 7) $\left(\sqrt{26}\right)^5$ or $\sqrt{26^5}$
- 8) $6^{1/2}$ and $19^{3/4}$
- 9a) 0.001
- 9b) 81
- 9c) 27
- 9d) $\approx 0.68$
- 10a) 0.64
- 10b) 0.0292
Roots Powers Ddfa99
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